Transoral three-dimensionally orthogonal intragastric spring systems, devices, methods of operation and manufacture are provided. A transoral three-dimensionally orthogonal intragastric spring system and/or device (and related methods of manufacture and operation) may reduce obesity or weight by stimulating the stomach walls of the patient. The three-dimensionally orthogonal intragastric spring device may be a purely mechanical device comprising a flexible body which in response to an input force in one direction, may deform and cause a resultant displacement in an orthogonal direction, thereby exerting a pressure on the inner stomach walls of the patient. Alternatively, a three-dimensionally orthogonal intragastric spring device may include a variable size balloon configured to occupy volume in the patient's stomach, thereby reducing the amount of space in the patient's stomach.